Statements of Consolidated Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Operating revenue:
Revenue	$ 41,303	$ 37,784	[1]	$ 36,558	[1]
Operating expense:
Salaries and related costs	11,458	10,941	[1]	10,176	[1]
Aircraft fuel	9,307	6,913	[1]	5,813	[1]
Regional capacity purchase	2,601	2,232	[1]	2,197	[1]
Landing fees and other rent	2,359	2,240	[1]	2,165	[1]
Depreciation and amortization	2,240	2,149	[1],[2]	1,977	[1],[2]
Aircraft maintenance materials and outside repairs	1,767	1,856	[1]	1,749	[1]
Distribution expenses	1,558	1,435	[1]	1,395	[1]
Aircraft rent	433	621	[1]	680	[1]
Special charges	487	176	[1]	745	[1]
Other operating expenses	5,801	5,550	[1]	5,317	[1]
Total operating expense	38,011	34,113	[1]	32,214	[1]
Operating income	3,292	3,671	[1]	4,344	[1]
Nonoperating income (expense):
Interest expense	(729)	(671)	[1]	(674)	[1]
Interest capitalized	70	84	[1]	72	[1]
Interest income	101	57	[1]	42	[1]
Miscellaneous, net	(76)	(101)	[1]	(11)	[1]
Total nonoperating expense, net	(634)	(631)	[1]	(571)	[1]
Income before income taxes	2,658	3,040	[1]	3,773	[1]
Income tax expense	529	896	[1]	1,539	[1]
Net income	$ 2,129	$ 2,144	[1],[2],[3],[4]	$ 2,234	[1],[2],[3],[4]
Earnings per share, basic (in dollars per share)	$ 7.73	$ 7.08	[1]	$ 6.77	[1]
Earnings per share, diluted (in dollars per share)	$ 7.70	$ 7.06	[1]	$ 6.76	[1]
United Airlines, Inc.
Operating revenue:
Revenue	$ 41,303	$ 37,784	[5]	$ 36,558	[5]
Operating expense:
Salaries and related costs	11,458	10,941	[5]	10,176	[5]
Aircraft fuel	9,307	6,913	[5]	5,813	[5]
Regional capacity purchase	2,601	2,232	[5]	2,197	[5]
Landing fees and other rent	2,359	2,240	[5]	2,165	[5]
Depreciation and amortization	2,240	2,149	[5],[6]	1,977	[5],[6]
Aircraft maintenance materials and outside repairs	1,767	1,856	[5]	1,749	[5]
Distribution expenses	1,558	1,435	[5]	1,395	[5]
Aircraft rent	433	621	[5]	680	[5]
Special charges	487	176	[5]	745	[5]
Other operating expenses	5,799	5,548	[5]	5,315	[5]
Total operating expense	38,009	34,111	[5]	32,212	[5]
Operating income	3,294	3,673	[5]	4,346	[5]
Nonoperating income (expense):
Interest expense	(729)	(671)	[5]	(674)	[5]
Interest capitalized	70	84	[5]	72	[5]
Interest income	101	57	[5]	42	[5]
Miscellaneous, net	(76)	(101)	[5]	(11)	[5]
Total nonoperating expense, net	(634)	(631)	[5]	(571)	[5]
Income before income taxes	2,660	3,042	[5]	3,775	[5]
Income tax expense	529	879	[5]	1,541	[5]
Net income	2,131	2,163	[6],[7],[8]	2,234	[6],[7],[8]
Passenger revenue
Operating revenue:
Revenue	37,706	34,460	[1]	33,429	[1]
Passenger revenue | United Airlines, Inc.
Operating revenue:
Revenue	37,706	34,460	[5]	33,429	[5]
Cargo
Operating revenue:
Revenue	1,237	1,114	[1]	934	[1]
Cargo | United Airlines, Inc.
Operating revenue:
Revenue	1,237	1,114	[5]	934	[5]
Other operating revenue
Operating revenue:
Revenue	2,360	2,210	[1]	2,195	[1]
Other operating revenue | United Airlines, Inc.
Operating revenue:
Revenue	$ 2,360	$ 2,210	[5]	$ 2,195	[5]

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) and Accounting Standards Update No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[2] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[3] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[4] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[5] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) and Accounting Standards Update No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[6] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[7] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[8] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.